Fabrication of maxillofacial surgical splints

ABSTRACT

A technique for fabricating a surgical splint for use in correcting a dental condition of a patient. The technique involves obtaining a three-dimensional digital model of lower and upper arch dentitions of the patient having the dental condition. Relative positions of the lower and upper arch dentitions are adjusted with respect to each other in the three-dimensional digital model using a computing device. A relative positioning structure is added to the three-dimensional digital model using the computing device. A physical model of the patient&#39;s corrected dentition is then generated from the three-dimensional digital model. The physical model includes the relative positioning structure that connects the lower and upper arch dentitions of the physical model at the adjusted relative position. The surgical splint is then formed using the physical model. A non-surgical splint is also described.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 13/956,593, filed on Aug. 1, 2013, which claims priority to U.S. Provisional Application Ser. No. 61/678,934 filed on Aug. 2, 2012, entitled FABRICATION OF MAXILLOFACIAL SURGICAL SPLINTS, the disclosures of which are hereby incorporated by reference in their entireties.

BACKGROUND

Maxillofacial surgery can be used to correct various deformities in the jaws. For example, maxillofacial surgery can be performed to address Class II overjet or Class III negative overjet. A Class II overjet occurs when the maxilla and upper teeth project further than the mandible and lower teeth. A Class III negative overjet is observable when the mandible and lower teeth project further than the maxilla and upper teeth.

Some maxillofacial surgery requires detaching the mandible. Then, the relative positioning of the maxilla and mandible is repositioned so that the Class II or Class III issue has been corrected. Splints are sometimes employed to maintain the maxilla and mandible at desired positions during the surgical procedure.

Splints are also sometimes used to change the positions of the upper and lower dentions for non-surgical purposes, including treatment of temporomandibular joint (TMJ) disorder or sleep apnea.

SUMMARY

In general terms, this disclosure is directed to the fabrication of maxillofacial surgical splints. In one possible configuration and by non-limiting example, the surgical splints are formed by using a model of the patient's dentition, where the model exhibits the desired relative positioning of the patient's dentition. In some embodiments the desired relative positioning is defined using an electronic model manipulation engine.

One aspect is a method of fabricating surgical splints for use in a surgical procedure. The method includes: obtaining a three-dimensional digital model of lower and upper arch dentitions of a patient having a dental condition; adjusting the relative position of the lower and upper arch dentitions with respect to each other in the three-dimensional digital model using a computing device; adding at least one relative positioning structure to the three-dimensional digital model using the computing device; generating a physical model of the patient's corrected dentition from the three-dimensional digital model, the physical model including the at least one relative positioning structure that connects the lower and upper arch dentitions of the physical model at the adjusted relative position; and forming a surgical splint using the physical model.

Another aspect is a physical model of a dentition of a patient, wherein the patient has a dental condition in which the upper and lower dentitions are in undesired relative positions. The physical model includes a physical model of the upper dentition; a physical model of the lower dentition; and a non-adjustable relative positioning structure arranged and configured to connect the physical models of the upper and lower dentitions in proper relative positions different from the undesired relative positions of the patient's upper and lower dentitions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic block diagram illustrating an example system for making and using a maxillofacial surgical splint.

FIG. 2 illustrates a side view of an example three-dimensional electronic model of dentition.

FIG. 3 illustrates a side view of an example three-dimensional electronic model of a patient's dentition.

FIG. 4 illustrates an example architecture of a computing device, which can be used to implement aspects according to the present disclosure.

FIG. 5 illustrates a schematic block diagram illustrating an example electronic model manipulation engine.

FIG. 6 illustrates a flow chart showing an example method of correcting improper alignment of the maxilla and the mandible.

FIG. 7 illustrates a side view of an example three-dimensional electronic model with corrected positioning of the maxilla and mandible.

FIG. 8 illustrates a screenshot of the upper arch dentition with relative positioning structures.

FIG. 9 illustrates a screenshot of the lower arch dentition with relative positioning structures.

FIG. 10 illustrates a perspective view of an example corrected arch dentition model with relative positioning structures.

FIG. 11 illustrates another perspective view of the example corrected arch dentition model with relative positioning structures.

FIG. 12 illustrates a cross sectional view of an example connection between two relative positioning structures.

FIG. 13 illustrates a front view of an example corrected arch dentition model with relative positioning structures.

FIG. 14 illustrates a left-side view of an example corrected arch dentition model with relative positioning structures.

FIG. 15 illustrates a right-side view of an example corrected arch dentition model with relative positioning structures.

FIG. 16 illustrates a front perspective view of an example physical model of a patient's corrected dentition.

FIG. 17 illustrates a rear perspective view of the example physical model of a patient's corrected dentition with relative positioning structures.

FIG. 18 illustrates a front perspective view of the example physical model of a patient's corrected dentition with a surgical splint.

FIG. 19 illustrates a rear perspective view of the example physical model of a patient's corrected dentition with relative positioning structures and with a surgical splint, as shown in FIG. 18.

FIG. 20 illustrates a front perspective view of the surgical splint, as shown in FIG. 18.

DETAILED DESCRIPTION

Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.

FIG. 1 is a schematic block diagram illustrating an example of a system 100 for making and using a maxillofacial surgical splint 108. In this example, the system 100 includes a scanning station 110, an orthognathic lab 112, and an operating room 114. The example scanning station 110 includes a dentition scanner 102 that generates an electronic model of a patient's dentition 104. The example orthognathic lab 112 includes a computing device 120, an electronic model manipulation engine 122, a corrected arch dentition model 124, a three-dimensional printer 126, a physical model of corrected dentition 128, and a splint forming station 130. The resulting physical splint can be used for orthognathic surgery in an operating room 114, for example, which can include an operating table 140. Also illustrated in FIG. 1 are examples of several people that may be involved with the system 100, including the patient P, orthodontist O, and surgeon S.

The scanning station 110 operates to perform a scan of the patient's P dentition, such as using a dentition scanner 102. In some embodiments, the patient P has been identified as having a dental condition in which the relative positioning of the maxillary and mandibular dentitions needs to be surgically adjusted. Several examples of such dental conditions include, but are not limited to, a Class II overjet or Class III negative overjet, temporomandibular joint (TMJ) disorder, or sleep apnea.

The scanner 102 operates to perform a scan of the patient's dentition. The scanner 102 can be one of several types, for example, including an intraoral scanner, a table top laser scanner, or a computed tomography (CT) scanner. In some embodiments, the scanner is a three-dimensional laser scanner that generates data defining a polygonal mesh forming the electronic model 104 of the dentition. In some embodiments, the scanner 102 first projects points onto the surface, here, the patient's dentition. The reflection of these points off of the patient's dentition enables the scanner to obtain the location of points in a three-dimensional coordinate system (x, y, z). These points are used to create a point cloud corresponding to the contours of the patient's dentition. Next, the scanning system creates a polygonal mesh by using the point cloud to create triangles that approximate the surface contours. Examples of scanners 102 include a 3D scanner, intraoral scanner, 3D intraoral scanner, or 3D dental scanner. The electronic model may be obtained by placing the scanner in the patient's mouth, by scanning a dental impression, or by scanning from outside of the mouth. Several examples of possible scanners 102 include: the TRIOS Intra Oral Digital Scanner, the Lava Chairside Oral Scanner C.O.S., the iTero, the Cerec AC, the Cyrtina IntraOral Scanner, a cone beam CT (CBCT) scanner, and an industrial CT scanner.

The electronic model of the dentition 104 includes, for example, the maxillary and mandibular dentition, and shows the undesired relative positioning of each that needs to be surgically corrected. Examples of such electronic models 104 are illustrated and described in more detail herein with reference to FIGS. 2 and 3.

The orthognathic lab 112 generates a physical splint 108 for use during the surgical procedure, using the electronic model of dentition 104. The example orthognathic lab 112 includes a computing device 120 including an electronic model manipulation engine 122, a three-dimensional printer 126, and a splint forming station.

The computing device 120 operates to generate a corrected arch dentition 124 using the electronic model of dentition 104. An example of the computing device 120 is illustrated and described in more detail herein with reference to FIG. 4. In some embodiments, the computing device 120 includes an electronic model manipulation engine 122. The user, such as an orthodontist, interacts with the computer 120 and electronic model manipulation engine to adjust the relative positioning of the maxillary and mandibular dentitions, and to insert a relative positioning structure, as discussed in more detail herein, to form a corrected arch dentition model 124. An arch dentition includes the dentition, gingiva, and contour of a patient's upper or lower jaw. An example of the electronic model manipulation engine 122 is illustrated and described in more detail herein with reference to FIGS. 5-6.

The three-dimensional printer 126 operates to generate a physical model 128 from the corrected arch dentition model 124. In some embodiments, the three-dimensional printer 126 uses an additive process of depositing successive layers of material onto a surface to manufacture a desired object. Electronic three-dimensional models provide the blueprint for the three-dimensional printer: software takes the object within the electronic model and creates thin, horizontal cross-sections which can be used to direct the printer to deposit material at locations defined by the electronic model. Examples of additive technologies include selective laser sintering, fused deposition modeling, stereo lithography, powder bed and inkjet head 3D printing, and plaster-based 3D printing. An example of a three-dimensional printer 126 is the ProJect line of 3D printers available from 3DSystems, Inc. of Rock Hill, S.C. Other examples of three-dimensional printers 126 are those available from Stratysis, Inc. of Eden Prairie, Minn., and Objet Ltd of Rehovot, Israel. In some embodiments the three-dimensional printer 126 is an inkjet printer that utilizes prints using a polymeric material. In another embodiment, the printer 126 is a stereolithography printer that utilizes a photocurable polymer. Other embodiments use other three-dimensional printers. An example of a physical model 128 created by the three-dimensional printer 126 from the corrected arch dentition model 124 are shown in FIGS. 16 and 17.

The splint forming station 130 uses the physical model 128 to form a physical splint 108 that can be used during a surgical procedure. In some embodiments, production of the surgical splint 108 involves inserting a pliable material, such as a light-curable resin, into a space between the upper and lower arch dentitions. In some embodiments, a non-stick coating is first applied to the upper and lower arch dentitions to permit the surgical splint to be more easily separated from the physical model. The pliable material contacts at least some of the teeth of the physical model and is therefore formed with imprints from the teeth that substantially match the shape of the patient's actual teeth. In some embodiments, the material is then cured by illuminating with an ultraviolet light, which hardens the material and decreases its pliability. One example of a suitable material that can be used to form the splint 108 is the TRIAD® transparent VLC custom tray material available from Dentsply International Inc., of York, Pa. In some embodiments, the material is a filled photocure dimethacrylate that polymerizes through exposure to 400- to 500-nm wavelengths ultraviolet-A light.

In some embodiments, the splint material has a paste consistency which can be applied by hand onto the physical model 128. A non-stick material can be applied to the physical model 128 prior to application of the splint material to assist in removal of the splint after it has been formed. The splint material is then placed onto the teeth of one of the upper or lower dentitions 162 and 164, and then the other dentition 162 or 164 is properly positioned using the relative positioning structures, causing the dentitions 162 and 164 to form imprints in the splint material. The splint material can then be hardened by exposing to UV light. The completed splint 108 is then removed from the physical model 128 and is ready for use. In some embodiments, the splint 108 is sterilized prior to use in a surgical environment of the operating room 114.

The surgical splint 108 is formed by the splint forming station, and can be used in some embodiments during a surgical procedure in the operating room 114 to assist in proper positioning of the patient's P maxillary and mandibular dentitions. An example of the surgical splint 108 is illustrated and described in more detail with reference to FIGS. 17-20. In other embodiments, the splint is a non-surgical splint that can be used, for example, to treat TMJ or sleep apnea.

In some embodiments, the surgical procedure is performed by a surgeon S in an operating room 114. The patient P can be supported on an operating table 140 or chair during the procedure. During an exemplary procedure, the patient's mandible is broken or cut to permit movement of the mandible. The surgical splint 108 is placed into the patient's mouth, and the maxillary and mandibular dentitions are properly aligned and positioned by locating the teeth in indentations in the surgical splint 108. The mandible is then reconnected to maintain the proper position of the mandible.

FIG. 2 illustrates an example of a side view of a three-dimensional electronic model of dentition 104, generated by the scanner 102, shown in FIG. 1. The illustrated electronic model 104A shows an example in which the patient has a Class II overjet, which can be identified by the relative positioning of the upper arch dentition 162 and the lower arch dentition 164. A Class II overjet can also be identified, for example, by the distance D1 between corresponding points on the upper dentition 162 and the lower dentition 164, where the upper dentition 162 extends forward farther than the lower dentition 164.

In some embodiments, overjet is identified by reference to particular points on the upper and lower dentitions 162 and 164. An example of such points include the points P1 and P2. Point P1 is the location of the most anterior cusp of the first molar on the upper dentition 162. Point P2 is the location between the anterior and posterior cusps of the lower first molar. In this example, it can be seen that there is a relatively large spacing between points P1 and P2, represented by distance D1, and the point P1 is forward of the point P2. Similarly, corresponding points on the other sides of the dentitions P1 and P2 can be evaluated. Finally, the alignment of the central incisors can be compared from the upper and lower dentitions 162 and 164, as it is typically preferred that the central incisors be aligned on the upper and lower dentitions 162 and 164.

The electronic model 104A of the upper arch dentition 162 defines the contours of the maxillary gingiva 166 and the maxillary teeth 168. Similarly, the electronic model 104A of the lower arch dentition 164 defines the contours of the mandibular gingiva 170 and the mandibular teeth 172. An example of a corrected relative positioning of the upper 162 and lower 164 dentitions is shown in more detail in FIG. 7.

FIG. 3 illustrates an example of a side view of a three-dimensional electronic model of a patient's dentition 104, generated by the scanner 102, shown in FIG. 1. The illustrated electronic model 104B shows an example of a Class III negative overjet, which can be identified by the relative positioning of the upper arch dentition 162 and the lower arch dentition 164. A Class II overjet can also be identified, for example, by the distance D2 between two or more corresponding points on the upper dentition 162 and the lower dentition 164, where the lower dentition 164 extends forward farther than the upper dentition 162.

In some embodiments, negative overjet is identified by reference to particular points on the upper and lower dentitions 162 and 164. An example of such points include the points P1 and P2, as discussed above. Point P1 is the location of the most anterior cusp of the first molar on the upper dentition 162. Point P2 is the location between the anterior and posterior cusps of the lower first molar. In this example, it can be seen that there is a relatively large spacing between points P1 and P2, represented by distance D2, and the point P2 is forward of the point P1.

The electronic model 104B of the upper arch dentition 162 defines the contours of the maxillary gingiva 166 and the maxillary teeth 168. Similarly, the electronic model 104A of the lower arch dentition 164 defines the contours of the mandibular gingiva 170 and the mandibular teeth 172. An example of a corrected relative positioning of the upper 162 and lower 164 dentitions is shown in more detail in FIG. 7.

FIG. 4 illustrates an exemplary architecture of a computing device that can be used to implement aspects of the present disclosure, including any of the plurality of computing devices described herein, such as a computing device of the dentition scanner 102, the electronic model manipulation engine 122, a computing device of the three dimensional printer 126, or any other computing devices that may be utilized in the various possible embodiments. The computing device illustrated in FIG. 4 can be used to execute the operating system, application programs, and software modules (including the software engines) described herein. By way of example, the computing device will be described below as the computing device 120 that operates the electronic model manipulation engine 122. To avoid undue repetition, this description of the computing device will not be separately repeated herein for each of the other possible computing devices, but such devices can also be configured as illustrated and described with reference to FIG. 4.

The computing device 120 includes, in some embodiments, at least one processing device 180, such as a central processing unit (CPU). A variety of processing devices are available from a variety of manufacturers, for example, Intel or Advanced Micro Devices. In this example, the computing device 120 also includes a system memory 182, and a system bus 184 that couples various system components including the system memory 182 to the processing device 180. The system bus 184 is one of any number of types of bus structures including a memory bus, or memory controller; a peripheral bus; and a local bus using any of a variety of bus architectures.

Examples of computing devices suitable for the computing device 120 include a desktop computer, a laptop computer, a tablet computer, a mobile computing device (such as a smart phone, an iPod® or iPad® mobile digital device, or other mobile devices), or other devices configured to process digital instructions.

The system memory 182 includes read only memory 186 and random access memory 188. A basic input/output system 190 containing the basic routines that act to transfer information within computing device 120, such as during start up, is typically stored in the read only memory 186.

The computing device 120 also includes a secondary storage device 192 in some embodiments, such as a hard disk drive, for storing digital data. The secondary storage device 192 is connected to the system bus 184 by a secondary storage interface 194. The secondary storage devices 192 and their associated computer readable media provide nonvolatile storage of computer readable instructions (including application programs and program modules), data structures, and other data for the computing device 120.

Although the exemplary environment described herein employs a hard disk drive as a secondary storage device, other types of computer readable storage media are used in other embodiments. Examples of these other types of computer readable storage media include magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, compact disc read only memories, digital versatile disk read only memories, random access memories, or read only memories. Some embodiments include non-transitory media. Additionally, such computer readable storage media can include local storage or cloud-based storage.

A number of program modules can be stored in secondary storage device 192 or memory 182, including an operating system 196, one or more application programs 198, other program modules 200 (such as the software engines described herein), and program data 202. The computing device 120 can utilize any suitable operating system, such as Microsoft Windows™, Google Chrome™, Apple OS, and any other operating system suitable for a computing device. Other examples can include Microsoft, Google, or Apple operating systems, or any other suitable operating system used in tablet computing devices.

In some embodiments, a user provides inputs to the computing device 120 through one or more input devices 204. Examples of input devices 204 include a keyboard 206, mouse 208, microphone 210, and touch sensor 212 (such as a touchpad or touch sensitive display). Other embodiments include other input devices 204. The input devices are often connected to the processing device 180 through an input/output interface 214 that is coupled to the system bus 184. These input devices 204 can be connected by any number of input/output interfaces, such as a parallel port, serial port, game port, or a universal serial bus. Wireless communication between input devices and the interface 214 is possible as well, and includes infrared, BLUETOOTH® wireless technology, 802.11a/b/g/n, cellular, or other radio frequency communication systems in some possible embodiments.

In this example embodiment, a display device 216, such as a monitor, liquid crystal display device, projector, or touch sensitive display device, is also connected to the system bus 184 via an interface, such as a video adapter 218. In addition to the display device 216, the computing device 120 can include various other peripheral devices (not shown), such as speakers or a printer.

When used in a local area networking environment or a wide area networking environment (such as the Internet), the computing device 120 is typically connected to the network through a network interface 220, such as an Ethernet interface. Other possible embodiments use other communication devices. For example, some embodiments of the computing device 120 include a modem for communicating across the network.

The computing device 120 typically includes at least some form of computer readable media. Computer readable media includes any available media that can be accessed by the computing device 120. By way of example, computer readable media include computer readable storage media and computer readable communication media.

Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any device configured to store information such as computer readable instructions, data structures, program modules or other data. Computer readable storage media includes, but is not limited to, random access memory, read only memory, electrically erasable programmable read only memory, flash memory or other memory technology, compact disc read only memory, digital versatile disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the computing device 120.

Computer readable communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” refers to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, computer readable communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared, and other wireless media. Combinations of any of the above are also included within the scope of computer readable media.

The computing device illustrated in FIG. 4 is also an example of programmable electronics, which may include one or more such computing devices, and when multiple computing devices are included, such computing devices can be coupled together with a suitable data communication network so as to collectively perform the various functions, methods, or operations disclosed herein.

FIG. 5 is a schematic block diagram illustrating an example of an electronic model manipulation engine 122. In this example, the model manipulation engine 122 includes a three-dimensional electronic model viewer 260, measurement and manipulation tools 262, and a relative positioning structure generator 264. Also illustrated in FIG. 5 are the electronic model of dentition 104 and the corrected arch dentition model 124 with relative positioning structure.

The three-dimensional electronic model viewer 260 operates to display the electronic model of dentition 104 generated by the dentition scanner 102 to a user, such as the orthodontist O, so that the user can view it. In one embodiment, the electronic model viewer 260 reads the received electronic model 104 data and renders the electronic model 104 viewable in the computing device 120. In some embodiments, the electronic model viewer 260 converts the file type of the received electronic model 104 into another format readable by the computing device 120, prior to displaying the electronic model of dentition 104 to the user O. An example of a three-dimensional electronic model viewer is the EMODEL (R) Viewer, such as version 8.5, available from GeoDigm Corporation, of Falcon Heights, Minn.

The measurement and manipulation tools 262 enable the user O to reposition the relative alignment of the upper 162 and lower 164 arch models. In one embodiment, the tools 262 render the upper 162 and lower 164 arch models independently maneuverable. In some embodiments, the user O utilizes the tools 262 to adjust the relative positions of the arch dentitions. The user O can reposition both the upper 162 and lower 164 arch models in any of the x-, y-, or z-planes to correct the diagnosed condition. In another embodiment, the tools 262 measure the relative positions of two or more corresponding points on the upper 162 and lower 164 arch models to obtain a distance D3. In this embodiment, the tools 262 are programmed to automatically compare the new distance D3 with a pre-defined metric automatically positioning the upper 162 and lower 164 arch models according to the pre-defined metric. Alternatively, the tools 262 can be used to instruct the user to continue repositioning the upper 162 and/or lower 164 arch models if the current relative positioning does not satisfy the metrics. In some embodiments, the measurement and manipulation tools 262 are part of the Modified Bite Module of the EMODEL® Viewer software application. For example, manipulation of the electronic model can be accomplished using the rotate x-y-z and translate x-y-z functions. Measurement can be accomplished, for example, using the measurement grid function. In another possible embodiment, the measurement and manipulation tools 262 can be configured to automatically configure the upper and lower dentitions 262 and 264 according to predefined criteria, or by user-provided criteria, such as desired measurements between particular points (e.g., P1 and P2 discussed herein, and the alignment of the central incisors).

In some embodiments, the tools 262 include a measurement tool for measuring the distance between at least two points of the upper and lower arch dentitions 162 and 164. An example showing the measurement of distance D4 after the repositioning of the upper 162 and lower 164 arch dentitions, is illustrated and described in more detail with reference to FIG. 7.

The relative positioning structure generator 264 operates to add to the electronic model 104 structures that will hold and maintain the relative positioning of the upper and lower arch dentitions 162 and 164, after the position of such arch dentitions 162 and 164 has been corrected in the electronic model 104. The relative positioning structure generator is illustrated and described in more detail with reference to FIG. 6.

FIG. 6 is a flow chart illustrating an example method 266 of correcting an improper alignment of the maxilla and the mandible. In this example, the method 266 includes operation 268 and methods 270 and 280. The method 266 transforms an electronic model of improperly aligned maxilla and mandible into a corrected model where the maxilla and mandible are properly aligned and the model has one or more relative positioning structures.

Operation 268 is performed to enable the user to view the electronic model of dentition 104. In some embodiments, operation 268 is performed by the three-dimensional electronic model viewer 260, shown in FIG. 5.

In this example, the method 270 is performed to adjust the relative positioning of the upper 162 and lower 164 dentition models, where the corrected relative positions are illustrated and described in more detail with reference to FIG. 7. The method includes operations 272, 274, and 276. In some embodiments, the method 270 is performed by the three-dimensional electronic model viewer 260 and the measurement and manipulation tools 262, shown in FIG. 5.

Operation 272 is performed to adjust the relative positions of the upper 162 and lower 164 arch dentitions. In some embodiments, the operation 272 interacts with the user to manipulate the relative positions of the arch dentitions 162 and 164. Based on the patient's condition, the operation 272 prompts the user O to reposition the patient's maxilla and mandible in the x-y plane, and receives inputs from the user to make the appropriate adjustments.

Operation 274 is performed to measure the relative positions of the upper 162 and lower 164 arch dentitions. In some embodiments, the operation 274 identifies two corresponding points on the upper 162 and lower 164 arch dentitions. As an example, the operation 274 calculates the distance, see D3 in FIG. 7, in the x-y-plane between two lines that pass through the identified points, where the lines are normal to the x-y-plane. For example, the operation 274 may select points on the labial surface of the maxillary and mandibular central incisors. In other embodiments, the operation 274 calculates the vertical distance between two corresponding points, see D4 in FIG. 7, on the upper 168 and lower 172 dentitions. For example, the operation 274 may select points on the occlusal surface of the 2^(nd) molars and calculate the vertical or z-plane distance between those points.

Operation 276 is performed to verify that the relative positioning of the upper 162 and lower 164 arch dentitions conforms to desired metrics. In some embodiments, pre-defined parameters are stored. An example of pre-defined parameters are metrics related to the required relative horizontal (x-y plane) positions of the upper 162 and lower 164 arch dentitions needed to correct the observed deficiency. Another example of pre-defined parameters are metrics corresponding to the manufacturing characteristics of the splint forming station 130. These parameters measure the z-plane or vertical distance between the upper 168 and lower 172 dentition.

In some embodiments, the operation 276 compares the relative position of the upper 162 and lower 164 arch dentitions. As an example, if the positions do not correspond to the desired metrics, the operation 276 prompts the user to readjust the relative positions in operation 272 and the process repeats until the arch dentitions are acceptably positioned. In one embodiment, if the relative positions do not conform to the pre-stored metrics, the operation 276 reposition the upper 162 and lower 164 arch dentitions so that the relative positions satisfy the metric criteria. As another example, if the positions are within acceptable tolerances of the pre-stored metrics, the operation 276 prompts the user to complete the model with operations 280 and 282. An example of a corrected arch dentition model 278 is illustrated and described in more detail with reference to FIG. 7.

In this example, the method 280 is performed to add relative positioning structures to the model. The method includes operations 282 and 284. In some embodiments, the method 280 is performed by the three-dimensional electronic model viewer 260 and the relative positioning structure generator 264, shown in FIG. 5. In some embodiments, the method 280 begins when the engine accesses the corrected arch dentition model 278. In some embodiments, the method 280 may be performed by a user who is not the orthodontist O.

Operation 282 is performed to add one or more relative positioning structures to the arch dentition model 278. In some embodiments, the operation 282 prompts the user to select a type of relative positioning structure from a database containing templates for different relative positioning structures.

In one embodiment, the operation 282 prompts the user to select a position for the relative positioning structure on the lower arch dentition 164, and the operation 282 receives the input from the user. In some embodiments, the operation 282 continues to prompt the user to select positions of additional relative positioning structures. Alternatively, the operation 282 prompts the user to select a position for the upper arch dentition 162 first; the order is not important. In some embodiments, the operation 282 adds one or more complementary relative positioning structures to the opposite dentition. In one embodiment, the operation 282 creates the relative positioning structures by accessing the templates defining the properties of the relative positioning structures.

FIGS. 8-15 illustrate an example of relative positioning structures as having cylindrical bases with male and female couplings, where the male coupling is in the shape of a truncated cone. This is only an example. In other possible embodiments, other shapes, configurations, and quantities of relative positioning structures can be used. Some examples include where the relative positioning structure is between or located on outside the upper and lower arch dentition. For example, a single structure that simultaneously holds the upper 162 and lower 164 arch dentitions, which is between the arch dentitions, or a c-shaped structure that holds the two arch dentitions without passing between the arch dentitions. In other embodiments, the relative positioning structure is a single structure, in contrast to the three structures shown in more detail in FIGS. 8-11, where the body has a larger surface area than the structures shown in FIGS. 8-11. In yet other embodiments, the relative positioning structure is two or more structures. In some embodiments, the relative positioning structures have bodies in other polyhedron shapes, such as triangular or rectangular prisms, in contrast to the cylindrical bodies shown in more detail in FIGS. 8-11. An example of the relative positioning structure is illustrated and described with reference to FIGS. 8-11.

Operation 284 is performed in some embodiments to ensure that the relative positioning structure or structures do not interfere with the subsequent surgical splint formation. In some embodiments, the operation 284 prompts the user to check the location of the relative positioning structure created by the operation 284 on the opposite dentition. In other embodiments, the operation 284 notifies the user that the current position of the relative positioning structure could interfere with the production of the surgical splint. As an example, the operation 284 accesses a database containing the various space requirements for different surgical splint production methods. Examples of such requirements could be the predicted width, in the x-y-plane, of surgical splints formed using different materials.

In some embodiments, the operation 284 receives the user's selection of new positions for the relative positioning structures. As an example, after receiving the user's input, the operation 284 updates the position of the complementary positioning structure. In one embodiment, the operation 284 repeats until the relative positioning structure or structures do not potentially interfere with the surgical splint production. In other embodiments, once the operation 284 has received the user's input selecting relative positioning structures, the model 124 is ready for the three-dimensional printer 126.

FIG. 7 illustrates a side view of an example of a corrected arch dentition model 278, such as generated by the method 270 shown in FIG. 6. In this example, the model 278 includes the upper 162 and lower 164 arch dentitions, the maxillary 166 and mandibular 170 gingiva, and the upper 168 and lower 172 dentition. In this example, upper 162 and lower 164 arch dentitions are positioned to correct the diagnosed condition of the patient P.

In some embodiments, the horizontal distance D3 is the distance in the x-y-plane between corresponding points on the upper 162 and lower 164 arch dentitions. In some embodiments, the two corresponding points are the same points used in measuring and obtaining the horizontal distance D1 or D2, as shown in FIGS. 2 and 3. In some embodiments, the vertical distance D4 is the distance in the x-z- or y-z-plane between two corresponding points on the upper 162 and lower 164 arch dentitions. In some embodiments, the electronic model manipulation engine 122 is used to obtain the model shown in FIG. 7.

FIG. 8 is a screenshot of the upper arch dentition 162 with relative positioning structures 290 as displayed by the electronic model manipulation engine 122, shown in FIG. 5. The screenshot shows the upper arch dentition 162, the upper dentition 168, the maxillary gingiva 166, and the location 292 of the relative positioning structures 290.

The relative positioning structure 290 functions to hold the upper 162 and lower 164 arch dentitions in the adjusted relative positions. In some embodiments, the relative positioning structures 290 in the upper arch dentition 162 have a shape that is complementary to the relative positioning structures 294, shown in FIG. 9, in the lower arch dentition 164. The relative positioning structures 290 are shown and described in more detail in FIGS. 10 and 12.

The location 292 of the relative positioning structures 290 functions to enable the relative positioning structures 290 to hold the physical model 128 in the adjusted positions without interfering with the surgical splint 108 production. In one embodiment, the engine 122 prompts the user to select a position 292 of a relative positioning structure 290, as described in operation 282. As an example, the engine 122 receives the input selecting the position 292, where the position 292 is preferably not in contact with the maxillary gingiva 166 or upper dentition 168. In another embodiment, the engine 122 prompts the user for the position 292 of two more relative positioning structures 290.

In some embodiments, the engine 122 corrects the location 292 of the relative positioning structures 290 so the structures do not interfere with the surgical splint 108 production. As an example, the engine 122 has verified that the location 292 of the relative positioning structures 290 in FIG. 8 do not interfere with the splint 108 production. The location 292 of the relative positioning structures 290 is also illustrated in FIG. 10.

FIG. 9 is a screenshot of the lower arch dentition 164 with relative positioning structures 294. The screenshot shows the lower arch dentition 164, the lower dentition 172, the mandibular gingiva 170, and the location 296 of the relative positioning structures 294.

The relative positioning structure 294 functions to hold the upper 162 and lower 164 arch dentitions in the adjusted relative positions 278. In some embodiments, the relative positioning structures 294 in the lower arch dentition 164 have a shape that is complementary to the relative positioning structures 290, shown in FIG. 8, in the upper arch dentition 162. The relative positioning structures 294 are shown and described in more detail in FIGS. 11 and 12.

The location 296 of the relative positioning structures 294 functions to enable the positioning structures 294 to hold the physical model 128 in the adjusted positions without interfering with the surgical splint 108 production. In one embodiment, the engine 122 prompts the user to select a position 296 of a relative positioning structure 294, as described in operation 282. As an example, the engine 122 receives the input selecting the position 296, where the position 296 is preferably not in contact with the mandibular gingiva 170 or lower dentition 172. In another embodiment, the engine 122 prompts the user for the position 296 of two more relative positioning structures 294.

In some embodiments, the engine 122 corrects the location 296 of the relative positioning structures 294 so the structures do not interfere with the surgical splint 108 production. As an example, the engine 122 has verified that the location 296 of the relative positioning structures 294 in FIG. 9 do not interfere with the splint 108 production. The location 296 of the relative positioning structures 294 is also described in FIG. 11.

FIG. 10 illustrates a perspective view of an example corrected arch dentition model 124 with relative positioning structures 290. The illustrated model shows an example of an upper arch dentition 162 in which there are three relative positioning structures 290 with a given radius R. Also illustrated is the location 292 of the structures 290, including an example coupling feature 300 and a body 302. The upper dentition 168 and the maxillary gingiva 166 are also shown.

The location 292 of the relative positioning structures 290 in FIG. 10 functions to stably connect to the lower arch dentition 164 while also not interfering with surgical splint 108 production.

The female coupling 300 on the relative positioning structure 290 receives the male coupling 308 from the opposite arch dentition. In one embodiment, the relative positioning structures 290 and 294 have complementary female 300 and male 308 couplings. In one embodiment, the female coupling 300 has a recessed portion that is sized and shaped to receive the corresponding protruding portion of the male coupling 308 (shown in FIG. 11). In this example, the female coupling 300 is on the relative positioning structures 290 in the upper arch dentition 162, but the engine can place the female coupling 300 on either the upper 162 or the lower 164 arch dentition. An example of a male-female coupling interaction is shown in more detail in FIG. 12.

The body 302 extends between the arch dentition 162 and the coupling 300. In some embodiments, the body 302 protrudes normal to the x-y-plane from the upper arch dentition 162. In one embodiment, the contours of the upper arch 162 flow seamlessly with the body 302 so that the three-dimensional printer 126 produces the upper arch 164 and positioning structures 290 as one continuous piece. In some embodiments, the body 302 of the relative positioning structure 290 is cylindrically shaped. In some embodiments, the engine 122 accesses a template which is used to create the relative positioning structure. As an example, the engine 122 receives the user's point selection of the center 292 of the positioning structure 290 as well as the desired radius R of the cylindrical body 302 extending therefrom. As another example, the engine 122 receives the user's selection of the height of the cylindrical body 302. The bodies and the connected relative positioning structures are shown in more detail in FIGS. 13-15.

FIG. 11 illustrates a perspective view of an example corrected arch dentition model 124 with relative positioning structures 294. The illustrated model shows an example of a lower arch dentition 164 in which there are three relative positioning structures 290 with a given radius R. Also illustrated is the location 296 of the relative positioning structures 294, an example male coupling 308 and support body 306 of a positioning structure, the lower dentition 172, and the mandibular gingiva 170.

The location 296 of the relative positioning structures 294 in FIG. 11 functions to stably connect to the upper arch dentition 162 while also not interfering with surgical splint 108 production.

The male coupling 308 on the relative positioning structure 294 fits into the female coupling 300 of the relative positioning structure 290 of the opposite arch dentition. In one embodiment, the relative positioning structures 290 and 294 have complementary female 300 and male 308 couplings. In one embodiment, the male coupling 308 is a truncated cone. In this example, the male coupling 308 is on the relative positioning structures 294 in the lower arch dentition 164, but the engine can place the male coupling 308 on either the upper 162 or the lower 164 arch dentition. An example of a male-female coupling interaction is shown in more detail in FIG. 12.

The body 306 supports the coupling 308. In some embodiments, the body 306 protrudes normal to the x-y-plane from the lower arch dentition 164. In one embodiment, the contours of the upper arch 162 flow seamlessly with the body 302 so that the three-dimensional printer 126 produces the upper arch 164 and relative positioning structures 290 as one continuous piece. In some embodiments, the body 306 of the relative positioning structure 294 is cylindrically shaped. In some embodiments, the engine 122 accesses a template which is used to create the relative positioning structure. As an example, the engine 122 receives the user's point selection of the center of the positioning structure 296 as well as the desired radius R of the cylindrical body 306 extending therefrom As another example, the engine 122 receives the user's selection of the height of the cylindrical body 306. The bodies and the connected relative positioning structures are shown in more detail in FIGS. 13-15.

FIG. 12 is a cross sectional view of the connection 301 between two example relative positioning structures 290 and 294. In this example, the connection 301 is between a female 300 and male 308 coupling, supported by the bodies 302 and 306 respectively, forming a snug fit 314 and 316, with voids 310 and 312. In other embodiments, the engine accesses templates containing different designs of relative positioning structures when the engine adds the positioning structures to the electronic model in operation 282. The connection 301 is shown in more detail in FIGS. 13-15.

The void 310 enables the male coupling 308 to fit within the female coupling 300 even if debris has settled within the female end's cavity or on the end of the male coupling. In some embodiments, the void's 310 space is formed between the top of the truncated cone male coupling 308 and the deepest part of the female coupling 300.

The voids 310 and 312 enable a snug fit between the male coupling 308 and the female coupling 300 even if debris has settled near the opening of the female coupling 300 or on the male coupling 308 close to where the coupling 308 meets the body 306. In some embodiments, the void 312 space is formed near the opening of the female coupling 300 and the body of the male coupling 308.

The two couplings 300 and 308 form a snug fit within the female coupling 314 and where the bodies meet 316. In some embodiments, the lateral surface of the male coupling 308 is flush with the lateral surface of the female coupling 300, forming an interface 314 where the two couplings are, or nearly are, in direct contact. In some embodiments, the surface of the bodies 302 and 306 that is parallel to the x-y-plane form an interface 316 where the two bodies are, or nearly are, in direct contact. In the preferred embodiment, the snug fit ensures that the upper 162 and lower 164 arch dentitions do not change their relative positions during the surgical splint forming (at station 130).

FIGS. 13-15 illustrate different views of the corrected arch dentition model 124 with connected relative positioning structures 328. FIG. 13 is a front view illustrating the upper 162 and lower 164 arch dentitions, the maxillary 166 and mandibular 170 gingiva, the upper 168 and lower 172 dentition, the connected relative positioning structures 328, and the midpoint x-y-plane 326 between the upper 162 and lower 164 arch dentitions. FIG. 14 is a left-side view illustrating the connected relative positioning structures 328. FIG. 15 is a right-side view also illustrating the connected relative positioning structures 328.

The connected relative positioning structures 328 hold the upper 162 and lower 164 dentitions in the relative positions defined by the orthodontist O 278. In a preferred embodiment, the upper 290 and lower 294 positioning structures interface 301 at the x-y-plane midpoint 326 between the upper 162 and lower 164 arch dentitions. In other embodiments, the interface 301 is located at positions other than the x-y-plane midpoint.

FIG. 16 is a front perspective view of a physical model 128 of a patient's corrected dentition. In this example, the physical model 128 includes the upper arch dentition 330 and the lower arch dentition 332. Present, but not visible in FIG. 16, are the connected relative positioning structures 342 which can be seen in FIG. 17. Additional exemplary views of the physical model 128 are also shown in FIGS. 17-19.

The upper arch dentition 330 of the physical model 128 of the patient's corrected dentition is a replication of the patient's upper dentition 334 and maxillary gingiva 336. In this embodiment, the physical model's 128 upper dentition 334 contours substantially match the patient's P actual upper dentition contours, so that a surgical splint can be made from the physical model 128 that fits snugly into the patient's dentition. The contours in the splint are shown in more detail in FIG. 20. In some embodiments, The upper arch dentition 330 is separable from the lower arch dentition 332, but the model 128 can be properly aligned and positioned by the connected relative positioning structures 342. The upper arch dentition 330 is also depicted in FIGS. 17-19.

The lower arch dentition 332 of the physical model 128 of the patient's corrected dentition is a replication of the patient's lower dentition 340 and mandibular gingiva 338. In this embodiment, the physical model's 128 lower dentition 340 contours substantially match the patient's P actual lower dentition contours, so that a surgical splint can be made from the physical model 128 that fits snugly into the patient's dentition. The contours in the splint are shown in more detail in FIG. 20. In some embodiments, the lower arch dentition 332 is separable from the upper arch dentition 330, but the model 128 can be properly aligned and positioned by the connected relative positioning structures 342. The lower arch dentition 332 is also depicted in FIGS. 17-19.

The distance D4 between two corresponding points on the upper 330 and lower 332 arch dentitions provides the space needed for the splint to fit during the operation. In one embodiment, the engine received the user's input of the distance D4 in methods 270 and 280, shown in more detail in FIG. 6. In some embodiments, the distance D4 corresponds to the surgical splint material's properties. In some embodiments, the distance D4 in the physical model 128 is maintained by the relative positioning structures 346 depicted in more detail in FIGS. 17 and 19.

FIG. 17 is a rear perspective view of a physical model of a patient's corrected dentition 128. In this example, FIG. 17 shows the upper 330 and lower 332 arch dentitions, and the connected relative positioning structures 342 formed by the positioning structures attached to the upper 344 and lower 346 arch dentitions. FIG. 19 shows a similar view with the surgical splint 108.

The connected relative positioning structures 342 function to hold the upper 330 and lower 332 arch dentitions in the relative positions defined by the orthodontist O. In this example, the interface between the upper 344 and lower 346 relative positioning structures occurs at the midpoint in the z-plane between the upper 330 and lower 332 arch dentitions. In some embodiments, the relative positioning structures 344 and 346 form a releasable coupling, shown in more detail in FIGS. 10-12. In some embodiments, the connected relative positioning structures 342 maintain the distance D4 between corresponding points, as shown in more detail in FIG. 16, to assist surgical splint formation and functionality.

The upper relative positioning structures 344 couple to the lower positioning structures 346 to form the connected relative positioning structures 342. In some embodiments, the upper 344 and lower 346 positioning structures extend from the surface contouring the patient's mouth that is not the dentition or gingiva. In some embodiments, the upper 344 and lower 346 positioning structures project a given distance away from the dentition so as to not interfere with the splint positioning or formation. In this example, the positioning structures 344 and 346 are cylindrical, as electronically depicted in FIGS. 10-11, and couple as depicted in FIG. 12.

FIG. 18 is a front perspective view of the physical model of the patient's corrected dentition 128 with the surgical splint 108. In this example, FIG. 18 shows the upper 330 and lower 332 arch dentitions, the upper 334 and lower 340 dentitions, and the surgical splint 108. A rear perspective view of the same is shown in FIG. 19, and the surgical splint 108 is shown in more detail in FIG. 20.

The surgical splint 108 maintains the relative positioning of the upper 330 and lower 332 arch dentitions as defined by the orthodontist O. Surgical splint formation techniques are described in more detail in FIG. 1, with reference to 130 and 108. In some embodiments, the upper surface of the surgical splint 108 has contours that match the contours of the patient's upper dentition 334. In some embodiments, the contours have a depth in a range from about 0.1 mm to about 3 mm. Other embodiments have other dimensions. Similarly, in some embodiments, the lower surface of the surgical splint 108 has contours that match the contours of the patient's lower dentition 340. In some embodiments, the contours have a depth in a range from about 0.1 mm to about 3 mm. Other embodiments have other dimensions.

FIG. 19 is a rear perspective view of the physical model of the patient's corrected dentition 128 with the surgical splint 108. In this example, FIG. 19 shows the upper 330 and lower 332 arch dentitions, the connected relative positioning structures 342, and the surgical splint 108. The surgical splint 108 is shown in more detail in FIG. 20.

The surgical splint 108 functions to hold the upper 330 and lower 332 arch dentitions in the relative positions as defined by the orthodontist O. In this example, the distance D4 between corresponding points is the same with the surgical splint 108 place between the upper 330 and lower 332 arch dentitions. In some embodiments, the connected relative positioning structures 342 are not in contact with the surgical splint 108.

FIG. 20 is a front perspective view of a surgical splint 108. In this example, FIG. 20 shows the surgical splint 108 with the contours 350 of the patient's upper dentition 334. In this example, the surgical splint also contains contours 350 on the opposing surface which correspond to the contours of the patient's lower dentition 340. Surgical splint formation techniques are described in more detail in FIG. 1, with reference to 130 and 108. In some embodiments, each of the patient's teeth has a corresponding contour 350 in the splint 108. In one embodiment, when the patient's teeth are placed in the splint, the relative positions of the upper 330 and lower 332 arch dentitions correct the diagnosed problem. In some embodiments, the splint 108 contours 350 are of a depth that will hold the upper 330 and lower 332 dentitions in the required relative positions but the splint 108 will also be removable from both the physical model 128 and the patient P.

The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims. 

1. A method of fabricating surgical splints for use in a surgical procedure, the method comprising: obtaining a three-dimensional digital model of lower and upper arch dentitions of a patient having a dental condition; adjusting the relative position of the lower and upper arch dentitions with respect to each other in the three-dimensional digital model using a computing device; adding at least one relative positioning structure to the three-dimensional digital model using the computing device; generating a physical model of the patient's corrected dentition from the three-dimensional digital model, the physical model including the at least one relative positioning structure that connects the lower and upper arch dentitions of the physical model at the adjusted relative position; and forming a surgical splint using the physical model.
 2. The method of claim 1, wherein the relative positioning structure includes separable first and second portions, the first portion connected to and extending from the upper arch dentition and the second portion connected to and extending from the lower arch dentition, wherein distal ends of the first and second portions have complementary mating features.
 3. The method of claim 2, wherein the complementary mating features are male and female couplings.
 4. The method of claim 1, wherein adding the at least one relative positioning structure comprises: prompting a user to identify a point on one of the digital model of the lower and the upper arch dentitions; receiving an input identifying a point; identifying a region surrounding the point having a predetermined radius; generating a body of the relative positioning structure extending from the region; and generating a coupling at an end of the body.
 5. The method of claim 4, wherein adding the at least one relative positioning structure further comprises: identifying a second point corresponding to the identified point on an opposite one of the lower and upper arch dentitions; identifying a second region surrounding the second point having the predetermined radius; generating a second body of a second relative positioning structure extending from the second region; and generating a coupling at an end of the second body, wherein the coupling at the end of the second body is complementary with the coupling at the end of the body to permit proper spacing and alignment of the lower and upper arch dentitions by mating the coupling with the second coupling.
 6. The method of claim 5, further comprising displaying the digital models of the upper and lower arch dentitions including the relative positioning structure and the second relative positioning structure and prompting the user to confirm that the relative positioning structure and the second relative positioning structure are adequately spaced from teeth in the digital models of the upper and lower arch dentitions.
 7. The method of claim 5, wherein when the relative positioning structure and the second relative positioning structure are mated together, teeth of the lower and upper arch dentitions are spaced from each other by a distance appropriate for a thickness of the surgical splint.
 8. The method of claim 7, wherein forming the surgical splint comprises: inserting a pliable material into the space between the lower and upper arch dentitions such that the pliable material includes an impression of at least some of the teeth of the lower and upper arch dentitions; and curing the pliable material using ultraviolet light to harden the material and reduce the pliability.
 9. The method of claim 1, generating a physical model comprises printing with a three-dimensional printer.
 10. The method of claim 1, wherein generating the physical model comprises milling the physical model from one or more blocks of material.
 11. A physical model of a dentition of a patient, the patient having a dental condition in which the upper and lower dentitions are in undesired relative positions, the model comprising: a physical model of the upper dentition; a physical model of the lower dentition; a non-adjustable relative positioning structure arranged and configured to connect the physical models of the upper and lower dentitions in proper relative positions different from the undesired relative positions of the patient's upper and lower dentitions.
 12. The physical model of the dentition of claim 11, wherein the physical model is configured to make a surgical splint, such that the non-adjustable relative positioning structure aligns the physical models of the upper and lower dentitions to reduce a space between predefined points as compared to a space between the same points on the patient's dentition prior to the surgical procedure.
 13. The physical model of the dentition of claim 11, wherein the physical model is configured to make a non-surgical splint, such that the non-adjustable relative positioning structure intentionally modifies the alignment of the upper and lower dentitions to achieve a therapeutic effect, such that a space between predefined points on the physical models of the upper and lower dentitions are greater than a space between the same points on the patient's dentition in its natural state.
 14. A method of fabricating a splint, the method comprising: obtaining a three-dimensional digital model of lower and upper arch dentitions of a patient having a natural alignment; adjusting the relative position of the lower and upper arch dentitions with respect to each other in the three-dimensional digital model using a computing device; adding at least one relative positioning structure to the three-dimensional digital model using the computing device; generating a physical model of the patient's corrected dentition from the three-dimensional digital model, the physical model including the at least one relative positioning structure that connects the lower and upper arch dentitions of the physical model at the adjusted relative position; and forming a splint using the physical model, wherein the splint is configured to provide a therapeutic effect by adjusting the alignment of the patient's upper and lower arch dentitions. 